A bar code wand reads a bar code symbol over which it is drawn by illuminating the symbol with a beam of light and detecting the amount of illuminating light reflected from the symbol. A bar code symbol generally consists of an alternating series of reflective and nonreflective bars in a linear pattern. The variations in reflective and nonreflective bars determines the amount of reflected light that is detected. The detected illuminating light is converted into an electrical signal which is processed to determine the information contained in the symbol. The variations in the amount of light contain information in the form of variations in duration of the electrical signals which result when the bar code wand is drawn across the bar code symbol.
Electronic components used in a bar code scanner are subject to manufacturing tolerances which cause some variability in the response of the bar code scanner to a given bar code symbol printed on a given surface. Also, a bar code scanner can be adjusted to have optimal performance in a given operating environment such as an application in which bar code symbols of a particular scale are used or in which the ambient lighting can produce difficult operating conditions. In addition, for wide market applicability, bar code scanners must be compatible with a variety of the readers that receive and decode the video signals which are produced by the bar code scanners and represent the information contained in a bar code symbol which has been scanned. It has been known in the past to provide bar code scanners with adjustable components whose settings are optimized by human technicians before the bar code scanners are used in the commercial world. However, this procedure is time consuming and expensive.